Ultrasonic carburetor system



Oct. 13, 1910 FIG. 2

FIG. 3

A. K. THATCHER 3,533,606

ULTRASONIC CARBURETOR SYSTEM Filed Feb. 6, 1968 ARTHUR K. THATCHERATTORNEY United States Patent O 3,533,606 ULTRASONIC CARBURETOR SYSTEMArthur K. Thatcher, P.0. Box 352, Merritt Island, Fla. 32952 Filed Feb.6, 1968, Ser. No. 703,333 Int. Cl. F02m 27/08 U.S. Cl. 261-1 5 ClaimsABSTRACT OF THE DISCLOSURE The sonic carburetor system includes a soundwave producing device positioned between an intake manifold opening anda fuel supply inlet in such a manner that fuel is drawn across theactive surface of the device by negative pressure from the intakemanifold. The carburetor system includes a novel fuel suply controlmechanism which employs a vector fluid switching device as a fuelcontrol unit for controlling the fuel supply volume to the sound waveproducing device.

The invention relates to carburetors generally, and more particularly toa novel and improved ultrasonic carburetor system for feeding fluid fuelto an internal combustion engine.

In the operation of internal combustion engines, the large amount ofunburned and partially burned contaminates produced by such enginesremains an unsolved but increasingly important problem. Not only doesthe production of such contaminates detract tremendously from theover-all efficiency of internal combustion engines as compared to othermotive sources, such as electric motors, but these contaminates aredischarged to produce noxious compounds which foul the air ofmetropolitan areas. Generally, most of these contaminates are the resultof incomplete combustion of fuel.

In an internal combustion engine, fuel is fed from a fuel tank into acarburetor unit which is in turn connected to the engine intakemanifold. During each suction stroke of the engine, air is drawn intothe carburetor and fuel is entrained in the air stream and mixedtherewith. However, conventional carburetor systems for internalcombustion engines are unable to produce consistent molecularsuspensions or emulsions of fuel molecules in the air stream, and largedroplets of fuel carried by the air stream into the engine causeinefficient and incomplete fuel combustion within the engine.

Attempts to develop carburetor systems which operate more effectively tofeed liquid fuel into combustion air at various engine speeds whilemaintaining a desirable air-fuel ratio have resulted in the developmentof complex carburetor systems containing mazes of small tubing,passageways, small jets, venturis and pumps. Such complex carburetorsystems are expensive, difficult to adjust and repair, and often aremerely a compromise between efiiciency, physical limitations and cost.These overly complicated systems are plagued by problems caused by smalldirt particles and other particles of foreign material commonly found infuels, and also generally have not increased the fuel combustion orefiiciency of internal combustion engines to satisfactory levels.

In recognition of the defects inherent in conventional complexcarburetor systems, attempts have been made to develop less complexcarburetors employing sonic or ultrasonic vibrators to achieve moreintensive atomization of fuel and therefore an even dispersion of liquidfuel in the combustion air stream. However, previous carburetor designsemploying sonic or ultrasonic mechanisms have failed to take intoaccount the varying conditions present within the carburetor of aninternal combustion engine as the engine operation varies, and thereforesuch ice previous carburetor designs are not elfective. For example,common fuels are not completely pure, and because water and otherimpurities in the fuels are less volatile than the fuel, it is necessaryto keep water droplets and other less volatile components of the fuel incontact with the main area of activity of the sound producing device ifsuch less volatile components are to be effectively added to thecombustion air within the carburetor. Generally, when fuel is applied toa transducer vibrator or other sound producing device, the fuel willflow to the first area of escape and will not necessarily cross the mostactive area of the device. Thus means must be provided to hold the lessmobile components of the fuel against the active area of the vibrator sothat these components can be added to the fuel-air emulsion. Thisprevious carburetor constructions employing sonic or ultrasonicvibrators have failed to do.

More specifically, previously known sonic or ultrasonic carburetorconstructions have failed to properly position the sonic or ultrasonicwave producing device with respect to the engine intake manifold and thecarburetor air inlet. This has resulted in fuel being diverted away fromthe active surface of the vibrator by the resultant negative pressure ofthe intake manifold as the speed of the internal combustion engineincreases. The vector forces created by this negative pressure of theintake manifold will overcome the force of gravity on fuel dropletsdirected toward a vibrator, and also will divert fuel which is directedunder pressure from a nozzle toward a vibrator. Thus, the vector forcesacting upon the fuel entering the carburetor must be taken into accountin positioning a sound wave producing device in or near the carburetorchamber.

it is a primary object of this invention to provide a novel and improvedcarburetor system which operates with high efficiency but is of simple,inexpensive construction and not hampered by complex components.

Another object of this invention is to provide a novel and improvedcarburetor system of simple construction which is less suscepta'ble tomalfunction due to the introduction therein of foreign particles thanconventional carburetor systems.

A further object of this invention is to provide a novel and improvedcarburetor system which operates todiminish the amount of unburned fuelin the exhaust of an internal combustion engine.

Another object of this invention is to provide a novel and improvedsonic carburetor system operative to provide an improved molecularsuspension or emulsion of fuel molecules with gas molecules.

A further object of this invention is to provide a novel and improvedsonic carburetor system which includes a sound wave producing componentlocated so that the vector force of the negative pressure from theinstake manifold of an internal combustion engine maintains fuel incontact with the active surface of the sound wave producing component.

Another object of this invention is to provide a novel and improvedsonic carburetor system which includes a vector fuel flow control unitoperative to control the flow of input fuel in accordance with theoperating condition of an internal combustion engine.

A still further object of this invention is to provide a novel andimproved sonic carburetor system which eliminates 'venturi fuel feedcomponents and employs a relative large fuel input jet means for fuelfeeding.

The above and further objects and details of this invention will bereadily apparent upon a consideration of the following specificationtaken with the accompanying drawings in which:

FIG. 1 is a diagrammatical longitudinal section of the carburetor systemof the present invention;

FIG. 2 is a diagrammatical longitudinal section of a second embodimentof the carburetor system of the present invention; and

FIG. 3 is a diagrammatical longitudinal section of a third embodiment ofthe carburetor system of the present invention.

Referring now to the drawings, the carburetor system of FIG. 1 includesa carburetor housing 12 which opens into the intake manifold of aninternal combustion engine at 14. The carburetor housing includes an airinlet opening 16 through which combustion air passes to the interior ofthe carburetor housing, and this opening may be provided with a closurevalve assembly 18. The valve assembly 18 may be of any suitableconstruction so long as this assembly operates effectively to close theopening 16 when the internal combustion engine connected to thecarburetor system 10 is not in operation, but to open and permit theflow of combustion air through the carburetor in response to negativepressure from the intake manifold. For purposes of illustration in FIG.1, the valve assembly 18 includes a valve 20 having a valve stem 22connected thereto which extends into a support 24 secured to the innersurface of the casing 12. The valve stem is movably mounted within thesupport 24 to permit movement of the valve 20 toward and away from aclosing position across the opening 16. A biasing spring 26 may beprovided to bias the valve 20 into a closed position across the opening16, so that combustion air will operate to open the valve against thebias of the spring 26'.

A butterfly control valve 28 of any suitable conventional type isprovided within the carburetor housing 12 between the combustion airinlet 16 and the intake manifold opening 14 to control the stream ofcombustion air passing through the opening 16 into the intake manifold.This butterfly control valve is mounted upon the casing 12 and operatesin a manner conventional to carburetors for internal combustion engines.

The fuel for the carburetor system 10 may be provided by pump or gravityflow from a fuel tank (not shown). Fuel so supplied from the fuel tankis passed from an input line 30 through a control mechanism 32 and intoan input line 34 which extends to a nozzle 36 within the carburetorhousing. The nozzle 36 includes a relatively large fuel orifice whichwill be less susceptible to clogging by dirt particles and whicheffectively feeds fuel into the carburetor housing 12 without requiringa high pressure fuel supply source. The novel arrangement of a soundwave producing device within the carburetor chamber in a manner to besubsequently described makes this low pressure fuel feed possible.

The fuel stream from the nozzle 36 is directed against the activesurface 38 of a sound wave producing device 40 which, for purposes ofdescription, will hereinafter be designated as a vibrator. This vibratorpreferably constitutes an ultrasonic transducer which is excited by anelectric connection 42 to a high frequency circuit, not shown. Althoughan electrically activated ultrasonic transducer is contemplated for useas the vibrator 40, it will be apparent that any suitable vibrationdevice capable of producing sound waves of sufficient power may beemployed. Ultrasonic frequency sound waves are preferred, but lowerfrequency sound waves, although greatly inefficient, would work ifenough power is employed.

The positioning of the vibrator 40 within the carburetor housing 12 iscritical, for the vector forces created by the negative pressure at 14from the intake manifold must be taken into account if the vibrator isto achieve an effective air-fuel emulsification. To insure that all ofthe components of the fuel, including the impurities, are homogenized oremulsified into the combustion air stream, it is necessary to hold theless mobile components of the fuel against the active surface of thevibrator 40. This is accomplished by causing the input fuel stream tofiow across the extent of the active surface of the vibrator so thatcomplete emulsification of the fuel and the impurities therein with thecombustion air within the carbureto housing 12 can occur. The fuel mustbe held against the active surface 38 of the vibrator and cannot bepermitted to flow to an area of escape through a low energy side of thevibrator.

In the carburetor system 10' of thepresent invention, the negativepressure from the intake manifold is employed to draw the input fuelfrom the nozzle 36 across the extent of the active surface 38 of thevibrator 40 and fuel-air emulsification occurs in a one-step process asthis fuel flow progresses. The vibrator is located between the nozzle 36and the entrance 14 to the intake manifold in such a manner that thenegative pressure from the intake manifold draws the fuel streamcompletely across the active surface of the vibrator. The nozzle 36 ispositioned at one extremity of the active surface of the vibrator andthe intake manifold opening is positioned at the opposite extremity.Therefore, there is no means by which the fuel is enabled to pass fromthe nozzle 36 into the opening 14 without first being drawn across theactive surface of the vibrator 40. Ideally, the vibrator is positionedat an angle so that the active face thereof intercepts the fuel streamfrom the nozzle 36. The fuel and the impurities therein areprogressively mixed with the air stream as the fuel moves across thevibrator surface.

It is obvious that fuel could be fed into the carburetor housing 12under the control of conventional fuel control means commonly employedin internal combustion engines, such as for example, a carburetor supplyfloat chamber including a float valve to control the level of fuelwithin the chamber. When such a chamber is employed, fuel is normallydrawn into the carburetor housing by means of the vacuum created by theintake manifold, or alternatively by gravity. However, in the carburetorsystem of the present invention, a static, fiuidics type switchingarrangement is used as the fuel feed control unit 32. This fuel feedcontrol unit receives fuel from a conventional fuel pump (not shown)through the line 30 and passes the fel through the control unit 32 andout through a return line 44 which provides a return circit for the fuelto the fuel tank. As the fuel passes through the control unit 32, a mainfuel line divider 46 is encountered which provides a split in the fuelstream so that some fuel may be diverted from the return circuit to thefuel tank and fed into the input line 34. The amount of fuel which isdiverted by the divider 46 into the input line 34 is determined by thespeed of the internal'combustion engine, for it is the increased vacuumfrom the intake manifold via the carburetor as the speed of the engineincreases which causes additional fuel to be diverted from the returncircuit 44. Ideally, the main inlet line 30 and the return line 44should be greater in diameter of the input line 34 to the carburetor topermit slower fuel flow in the return line and more precise control offuel to the carburetor. Also, the angle of the divider 46 between theinlet line 30 and the input line 34 should be great enough so as not topermit fuel to enter the carburetor before the engine is turned over. Ifthe angle is great, there is less chance of accidental fuel feed to thecarburetor when the engine is not running, but too great an angle canresult in a turbulent fuel fiow through the input line 34. vIt has beenfound that a divider angle within the range of from 45 to 60 degrees isquite effective.

In the operation of the carburetor 10 of FIG. 1, when the internalcombustion engine associated with the system is started, negativepressure from the opening 14 into the intake manifold causes fuel to bediverted within the fuel feed control unit 32 so that a small fuel inputflows through the inlet line 34. This fuel is projected upon the face ofthe vibrator 40 which is vibrating within the ultrasonic frequencyrange. It has been found, for example, that if the vibrator 40constitutes an electronic transducer, this transducer operates well whenthe frequency used is approximately 860 kc. and the transducer ispowered at or above 2 watts per square centimeter. With the fuel flowingin through the input line 34 onto the lowermost extremity of thetransducer, the vacuum from the intake manifold draws the fuel acrossthe active surface 38 of the vibrator, maintaining the fuel andimpurities therein in contact with the active surface. As the fuelstream moves, the vibration of the vibrator accomplishes a molecularsuspension of fuel in air in one step. The air has been drawn in fromthe inlet opening 16 by the vacuum from the intake manifold, and theinflux of air causes the valve 20 to open against the bias of the spring26. As the speed of the engine increases, the vacuum or negativepressure from the intake manifold increases, and increased air is drawnin through the air inlet opening 16. Also, increased fuel flow isdiverted through the fuel inlet 34 from the fuel return circuit 44.

When the internal combustion engine is shut down, the negative pressurefrom the intake manifold drops and air and fuel are no longer drawn intothe carburetor hous ing 12. However, a vaporized fuel and air mixturemay still be present to some extent in the carburetor housing for ashort period after the internal combustion engine ceases operation, andit is desirable to provide the valve 20 which will close immediatelyupon shut down of the engine to prevent this mixture from escaping intothe atmosphere.

It is often desirable to provide a one-way check valve 48 in the fuelreturn line 44 to prevent air from accumulating in the return line whenfuel is diverted into the input line 34, and to give maximum fulldelivery to the engine.

The carburetor system of FIG. 1 may be modified constructionally toadapt the system for a wide variety of uses, the primary constructionallimitation being that the vibrator be positioned within the carburetorhousing relative to the intake manifold opening and the fuel input sothat negative pressure from the intake manifold draws the input fuelacross the active surface area of the vibrator. Once such modificationof the carburetor system 10 is illustrated in FIG. 2 wherein, forpurposes of clarity, like reference numerals are employed to indicatesystem components common to FIGS. 1 and 2.

Referring now to FIG. 2, it will be noted that the fuel input nozzle 36is arranged relative to the vibrator 40 so that fuel is directed againstthe central portion of the active surface 38 of the vibrator rather thanagainst the outer extremity of the active surface as indicated inFIG. 1. In this embodiment, the active surface of the vibrator, insteadof merely being slightly inclined relative to the fuel nozzle 36 asindicated in FIG. 1, is positioned substantially perpendicular to thecentral longitudinal axis of the nozzle. The opening 14 to the intakemanifold for the internal combustion engine is positioned beneath theactive surface of the vibrator, while the nozzle 36 is positioned abovethe vibrator. Thus the negative pressure from the intake manifold drawsfuel from the nozzle 36 into contact with the central portion of theactive surface 38 of the vibrator. Once the fuel is drawn into contactwith the vibraor, it then is drawn outwardly from the central portion ofthe active surface of the vibrator to the outer extremities thereof. Itis apparent that the fuel flows across the surface of the vibrator andis held in contact therewith by the negative pressure from the intakemanifold, so that an effective fuel-air emulsion occurs with thecombustion air being drawn inwardly from air intake 16. This emulsifiedfuel-air mixture is then drawn through a filter or screening unit 50which extends between the vibrator 40 and walls of the carburetorhousing 12 and into the intake manifold for the internal combustionengine.

For more effective engine idling, it is sometimes desirable to modifythe fuel control unit 32 of FIG. 1 to add additional vacuum bleed-offlines extending to the interior of the carburetor housing 12. Althoughany desirable number of such branch bleed-01f lines may be employed, forpurposes of illustration, one additional bleedolf line 52 is shown inFIG. 2. This additional bleed-off line extends from the full inlet line30 into the carburetor housing 12 and operates to divert additional fuelfrom the fuel return system 44. The additional bleed-off line 52 actingon the side of the fuel stream as it flows from the inlet 30 to returnline 44 operates to draw additional fuel through the line 34 when theengine is idling. These additional bleed-off lines are sometimesnecessary to insure effective engine idling, and it is apparent that acontrol system 32 containing a plurality of such bleed-off lines may beemployed with the carburetor units of either FIGS. 1 or 2.

In the carburetor constructions of both FIGS. 1 and 2, it is importantto carefully position the apex point of the divider 46 with respect tothe end of the nozzle 36. The apex of the divider should be spaced fromthe end of the nozzle a distance which is equal to at least five timesthe diameter of the nozzle. This will insure that proper switching ofthe fuel stream will occur.

Referring now to FIG. 3, it will be noted that it is possible toposition the vibrator 40 externally of the carburetor housing 12 bymounting the vibrator around a modified fuel nozzle 36. Again, as in theembodiments illustrated by FIGS. 1 and 2, the vibrator 40 of FIG. 3 willoperate effectively so long as it is positioned in a manner whereby thefuel provided to the vibrator is drawn across the active surface thereofby the negative pressure from the intake manifold.

It will be noted in FIG. 3 that the fuel inlet 30 connects into a tube56 which forms the nozzle 36. The tube 56 is composed ofmagnetostrictive material, and the inner bore of the tube forms theactive surface 38 for the vibrator 40. Also, it will be noted from FIG.3 that the outlet end of the inner bore of the tube 56 is flaredoutwardly, as indicated at 58, to provide an outlet opening of greaterdiameter than the inlet at the fuel inlet line 30. This flared outletfacilitates the emulsion of fuel with air as the fuel is drawn from theactive surface 38 into the carburetor chamber.

A support collar 54 is secured to the outer surface of the carburetorhousing 12 and mounts a high frequency electro-magnetic coil 60 on thecarburetor housing. The coil 60 surrounds the magnetostrictive tube 56and combines with the magnetostrictive tube to form the sound waveproducing device or vibrator 40. Power for the electromagnetic coil 60is provided by an input connection 62.

In the operation of the carburetor of FIG. 3, fuel from the fuel tankflows into the inlet line 30 and is drawn across the active surface 38of the magnetostrictive tube 56 by the negative pressure from the enginemanifold. The magnetostrictive tube and the electromagnetic coil 60combine to provide a sound wave producing device 40, and it will benoted that the input fuel is caused to pass completely across the activesurface 38 of this device. Subsequently, the fuel particles mix with theair from the air inlet 16 in the flared portion 58 of the nozzle 36 andalso in the carburetor chamber. This fuelair emulsion is then drawn intothe manifold by the negative pressure at the manifold connection 14.

The nozzle 36 of FIG. 3 may be connected'to receive fuel from a fuelfeed control unit of the types illustrated at 32 in FIGS. 1 and 2 ifdesired.

It will be readily apparent to those skilled in the art that thecarburetor system of the present invention provides a simple, effectivecarburetor system employing a minimum number of movable parts whichoperates to achieve an enhanced fuel-air emulsification. The arrangementand types of components employed herein may be subject to numerousmodifications well within the purview of this inventor who intends onlyto be limited to a broad interpretation of the specification andappended claims.

What is claimed is:

1. A carburetor system for connection between a fuel source and theintake manifold of an internal combustion engine comprising a carburetorhousing defining an internal carburetor chamber, said housing includingan opening to said intake manifold formed therein, and an air intakeopening positioned above said manifold opening, said manifold and airintake openings being relatively positioned to cause air to passdownwardly through said air intake opening into said carburetor chamberand laterally of said chamber into said manifold opening, fuel inputmeans connected from said fuel source to said carburetor housing, saidfuel input means including a nozzle opening into said chamber oppositesaid manifold opening at a level below that of said manifold opening fordirecting fuel into said carburetor chamber, and a sound wave producingunit having a flat active vibrating surface mounted within saidcarburetor chamber and extending across said carburetor chamber betweensaid nozzle and the opening to said intake manifold in a manner to causenegative pressure from said intake manifold to draw fuel across theextent of said active surface in contact therewith, said active surfacebeing inclined upwardly relative to the central longitudinal axis ofsaid nozzle and including a first outer extremity positioned to receivefuel from said nozzle and a second outer extremity opposite to andspaced from said first outer extremity, said second outer extremitybeing positioned toward said intake manifold opening above said firstouter extremity.

2. The carburetor system of claim 1 wherein said nozzle is positionedabove said first outer extremity of said active surface, said activesurface being inclined to an extent whereby said second outer extremitythereof extends upwardly to a point above said nozzle.

3. The carburetor system of claim 1 wherein said fuel input meansincludes a fuel feed control assembly connected between said fuel sourceand said nozzle, said fuel feed control assembly including a main fuelline connected to receive fuel from said fuel source and to return fuelto said fuel source, and a branch line of samller diameter than saidmain line extending from said main line to said nozzle, the juncturepoint between said main and branch lines being spaced from the end ofsaid nozzle a distance equal to at least five times the diameter of saidnozzle.

4. The carburetor system of claim 3 wherein said branch line to saidnozzle extends above and away from a juncture point with said main lineat an agle within the range of from to 5. The carburetor system of claim4 wherein at least one vacuum vector control line extends from ajuncture point with said main line to said carburetor chamber, saidbranch line extending from a point on said main line between said nozzleand the juncture point of said vacuum vector control line.

References Cited UNITED STATES PATENTS 890,970 6/1908 Durr 261-36 X1,809,531 -6/1931 Pogue 261-36 2,791,990 5/1957 Grieb 261-1 X 2,791,9945/1957 Grieb 261-1 X 2,908,443 10/1959 Fruengel.

3,258,254 6/1966 Jakob 261-36 3,386,710 6/1968 York 261-36 3,389,8946/1968 Binder 261-36 3,406,951 10/1968 Marks 261-36 FOREIGN PATENTS493,912 5/1954 Italy.

TIM R. MILES, Primary Examiner U.S. Cl. X.R.

